Our goal is to develop nonsubjective methods to evaluate protein crystal perfection and to use these methods to to objectively evaluate and compare various methods of protein crystal growth and data collection. Our results will be applied to comparing microgravity versus earth-bound crystal growth and to comparing cryogenic data collection methods. This proposal contains an integrated program to fully characterize protein crystal quality and to correlate crystal quality with crystal morphology, growth conditions and cryogenic data collection. Measurements of crystal quality will include topography, rocking-width mosaicity measurements and standard high-resolution data collection. We will examine protein crystal perfection where the following conditions have been met: (1) different crystal morphologies are available for the same protein, (2) microgravity grown samples are available and (3) cryogenic conditions have been established.